Update controller and remote to rolling code?

Please advise. I have Model 55B Overhead door in great condition and I have need of 2 more remotes. Is it feasible to update my system so that I can have the more secure "rolling code" remotes?

It appears that the total cost of 2 of the older remotes is going to be in excess of $50. Thanks for your time and suggestions!

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They do make kits to use rolling code transmitters, but the receiver is simply wired in parallel with the wall control.

You can see one at http://www.amazon.com/gp/product/B000EN46NK?ie=UTF8&tag=dietingsuckso-20&linkCode=xm2&camp=1789&creativeASIN=B000EN46NK

If that is what you want, you can order extra remotes at http://www.amazon.com/gp/product/B000KKXR0K?ie=UTF8&tag=dietingsuckso-20&linkCode=xm2&camp=1789&creativeASIN=B000KKXR0K